Spellscorn

Null

When you take this archetype at 3rd level, you manifest a magical dead zone around yourself. While you are conscious, you resist damage from cantrips and 1st-level spells. This resistance increases to 2nd-level spells at 7th level, 3rd-level spells at 15th level, and 4thlevel at 18th. You also gain a new reaction. When a creature you can see casts a spell, you can use your reaction to lower the save DC for that spell by half your fighter level. This decrease applies to you and all creatures within 10 feet of you. You can use this reaction a number of times equal to your Intelligence modifier (a minimum of 1) and recover all uses after a short rest.

Inquisitor

Starting at 7th level, you can hunt mages with unparalleled skill. You gain proficiency in Arcana, and have advantage on checks to identify spells or other magical effects. You can identify a spell being cast without using a reaction. You can also cast detect magic at will. When you spend at least 1 minute observing or interacting with another creature outside of combat, you learn about its magical capabilities. You learn whether or not it can cast spells, along with two of the following:

• the creature's spell save DC
• its current number of unexpended spell slots
• its caster level, if it has one
• its caster class, if it has one
• if the creature has the innate spellcasting trait, and how many spells it can cast each day
• any two spells that it knows from a school of your choice 
• 1 magical item that it has on its person

Weavecutter

Starting at 10th level, your attacks breach magical resistances, wards, and effects. Your weapon attacks are considered magical and ignore any magical effects or magic items that increase a creature's Armor Class, such as +1 armor or the Shield spell. When you damage a spellcaster who is concentrating on a spell, the DC for their Constitution saving throw to retain concentration is 10 or the total damage you dealt, whichever is higher.

Arcane Battery

Starting at 15th level, you can absorb the power of magical items, weakening them while strengthening yourself. Once per turn when you damage a creature with a weapon attack you can absorb the power of a magical item of your choice that they are wearing, carrying, or attuned to. That magical item becomes inert for 1d4-1 rounds, during which time none of its properties apply to the user, and none of its special abilities, spells, or properties can be used. You also gain a number of temporary hit points based on the item's rarity, detailed below. You lose these temporary hit points when the item becomes active again.

Item Rarity	Tempory HP gained
Common	10
Uncommon	20
Rare	30
Very Rare	50
Legendary	80
Artifact	120

 

Spell Deflection

At 18th level, you can turn the magic of your foes against them. You are immune to the damage of and effects from spells that Null grants resistance to. Whenever you are hit with one of those spells, can use your reaction to reflect the spell back at its caster, dealing half the spell's normal damage. If the spell does not deal damage, this feature has no effect.